High-speed centrifugation rather than Lipoclear reagent can be used for removing the interference of lipemia on serological tests of infectious diseases: AIDS, hepatitis B, hepatitis C, and syphilis by chemiluminescent microparticle immunoassay.

The aim of this study was to investigate the interference of lipemia on measurement of HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc, anti-HCV, HIV Ag/Ab, and anti-TP in serum by chemiluminescent microparticle immunoassay (CMIA) and compare lipemia removing performance between high-speed centrifugation and Lipoclear reagent. Mixed native serum samples (NSs) and hyperlipemia serum samples (HLS) were prepared for the investigated parameters. The levels of these parameters in NS and HLS were determined by CMIA on an Abbott ARCHITECT i2000SR immunoassay analyzer. HBsAg, anti-HBs, and anti-TP were affected with relative bias >12.5% (acceptable limit) when the level of triacylglycerol (TG) was higher than 27.12 mmol/L in HLS. Clinically unacceptable bias were observed for HBeAg and anti-HBe in HLS with TG higher than 40.52 mmol/L. However, anti-HCV and HIV Ag/Ab were not interfered in severe lipemia with TG < 52.03 mmol/L. In addition, the Lipoclear reagent did not reduce the interference of lipemia with relative bias from -62.50% to -18.02%. The high-speed centrifugation under the optimized condition of 12 000g for 10 min successfully removed the interference of lipemia with relative bias from -5.93% to 0% for HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc, and anti-TP. To conclude, high-speed centrifugation can be used for removing the interference of lipemia to measure HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc, and anti-TP. Accordingly, a standardized sample preanalytical preparation of the patients and other screening participants as well as a specimen examination procedure for removing lipemia interference on the serological tests was recommended.

Overexpression of MiR-633 Suppresses the Tumorigenicity of Gastric Cancer Cells and Induces Apoptosis by Targeting MAPK1.

OBJECTIVE: MicroRNA (miRNA/miR)-633 is dysregulated in several types of cancers and is involved in tumorigenesis. However, the function and role of this miRNA in gastric cancer (GC) are not fully understood. The aim of the present study was to evaluate miR-633 expression in GC cell lines and in GC tissue vs. adjacent normal tissue, and to determine its association with clinicopathological data. This work was extended to investigate the effects of miR-633 overexpression on tumor cells in vitro. METHODS: Reverse transcription-quantitative PCR (RT-qPCR) was used to detect and compare the expression level of miR-633 in GC cells, as well as in GC and normal adjacent tissue samples. The clinical significance of miR-633 was also analyzed. MiR-633 lentivirus (LV-miR-633) and negative control lentivirus (LV-NC) were generated and used to transduce SGC-7901 and HGC-27 GC cells in order to analyze the effect of miR-633 on their phenotype. The effects of miR-633 overexpression on GC cell proliferation, apoptosis, migration and invasion were investigated. The target gene of miR-633 was predicted, then confirmed using a dual luciferase reporter gene assay, RT-qPCR and Western blotting. RESULTS: MiR-633 was significantly downregulated in GC cell lines, as well as in GC tissue compared with adjacent normal tissue. Moreover, miR-633 expression was associated with the tumor/node/metastasis (TNM) stage, invasion depth, Borrmann classification and lymph node metastasis (P<0.05). Compared with the LV-NC group, transduction with LV-miR-633 reduced the proliferation, the number of clones, the wound healing rate, the number of invading cells and the number of cells in the G1 phase of the cell cycle (P<0.01). LV-miR-633 also increased the apoptosis rate (P<0.01). The expression level of mitogen-activated protein kinase (MAPK) 1, high-mobility group box 3 (HMGB3), claudin 1 (CLDN1) and MAPK13 were downregulated in LV-miR-633-transduced cells (P<0.01). The dual luciferase reporter assay confirmed that the 3'-untranslated region of MAPK1 was the target site of miR-633 (P<0.01). CONCLUSION: MiR-633 acts as a tumor suppressor in GC, and its expression level is associated with TNM stage, invasion depth, Borrmann type and lymph node metastasis. Overexpression of miR-633 inhibits the proliferation and migration of GC cells and induces apoptosis and cell cycle arrest at the in G1 phase. In addition, miR-633 negatively regulates the expression of MAPK1, HMGB3, CLDN1 and MAPK13 and directly targets MAPK1.

The endogenous factors affecting the detection of serum SARS-CoV-2 IgG/IgM antibodies by ELISA.

To investigate endogenous interference factors of the detection results of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgM/IgG. Enzyme-linked immunosorbent assay (ELISA) was used to detect SARS-CoV-2 IgM/IgG in sera of 200 patients without COVID-19 infection, including rheumatoid factor (RF) positive group, antinuclear antibody (ANA) positive group, pregnant women group, and normal senior group, with 50 in each group and 100 normal controls. The level of SARS-CoV-2 IgG in pregnant women was significantly higher than that in the normal control group (p = 0.000), but there was no significant difference between other groups. The levels of SARS-CoV-2 IgM in the pregnant women group, normal senior group, ANA positive group, and RF positive group were significantly higher than that in the normal control group (p < 0.05), with significant higher false-positive rates in these groups (p = 0.036, p = 0.004, p = 0.000, vs. normal control group). Serum RF caused SARS-CoV-2 IgM false-positive in a concentration-dependent manner, especially when its concentration was higher than 110.25 IU/L, and the urea dissociation test can turn the false positive to negative. ANA, normal seniors, pregnant women, and RF can lead to false-positive reactivity of SARS-CoV-2 IgM and/or IgG detected using ELISA. These factors should be considered when SARS-CoV-2 IgM or IgG detection is positive, false positive samples caused by RF positive can be used for urea dissociation test.

Unmatched Virus Preservation Solution may Impede One-Step Reagent for Detection of 2019-nCoV RNA.

BACKGROUND AND METHODS: 2019 Corona Virus Disease (COVID-19) caused by SARS-CoV-2 is still pandemic now. RT-qPCR detection was the most common method for the diagnosis of SARS-CoV-2 infection, facilitated by amounts of nucleic acid testing kits. However, the accuracy of nucleic acid detection is affected by various factors such as specimen collection, specimen preparation, reagents deficiency, and personnel quality. RESULTS: In this study, we found that unmatched virus preservation solution will inhibit N gene and OFR-1ab gene (two independent genes of SARS-CoV-2) amplification in one-step detection reagent. CONCLUSIONS: Despite just being a particular phenomenon we found in our work to fight 2019-nCoV, we concluded that unmatched virus preservation solution may have an inhibitory effect on SARS-CoV-2 nucleic acid detection which may lead to incorrect clinical diagnosis.

Dynamic monitoring of immune function indexes in COVID-19 patients.

We conducted a retrospective analysis of the clinical characteristics and dynamic variations of immune indexes in nine COVID-19 patients in Zigong, China. We used flow cytometry and enzyme-linked immunosorbent assays to measure the absolute levels of CD4 and CD8 lymphocytes and SARS-CoV-2 antibodies, respectively. We found that CRP, LDH, HBDH, CD4/CD8 and IgE levels were increased in 6/9 patients, while PA and the absolute numbers of CD4 and CD8 lymphocytes decreased in 7/9 patients. From disease onset through 63 days of follow-up, SARS-CoV-2 IgG levels were consistently higher than those of SARS-CoV-2 IgM, reaching peaks on days 28 and 13, respectively. IgM levels decreased to normal 35 days after disease onset, while IgG levels remained elevated through day 63. IgE levels varied similarly to SARS-CoV-2 IgM. Our results suggest that SARS-CoV-2 may elicit allergic immune responses in patients and that the levels of CRP, PA, LDH, and HBDH, as well as the absolute numbers of CD4 and CD8 lymphocytes could be used as early diagnostic markers of SARS-CoV-2 infection. Lastly, the dynamic variation of SARS-CoV-2 antibodies could guide the timing of blood collection for plasma exchange.

Composite Plate Rolling Technology of 304/Q345R Based on a Corrugated Interface.

A new rolling process of the 304/Q345R composite plate based on a corrugated interface was developed. Through numerical simulation and rolling experiments, the metal deformation law, the stress and strain field distribution, and the bond strength of the corrugated plate were studied. By comparison, the corrugated interface effectively increased the length of the composite interface. Also, the composite interface from the 2D corrugated surface became a 3D corrugated surface, and a combination of the 304/Q345R composite plate metallurgy was achieved with a low reduction rate. Simultaneously, the interface bonding strength was improved.